| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical hybrid circuit and an optical receiver capable of obtaining stable characteristics and enhancing the degrees of freedom of design, and to provide an optical coupler that can be suitably used for the optical hybrid circuit.SOLUTION: An optical hybrid circuit 100 comprises a parallelogram-shaped 2:2 optical coupler 1 and a parallelogram-shaped 4:4 multi-mode interference coupler 2, and a rectangular-shaped output side 2:2 optical coupler 3. By subordinately connecting these couplers, an optical 90° hybrid circuit is attained having a structure where two output waveguides 19 and 20 constituting an output channel are arranged contiguously. Depending on inclination angles of the parallelograms, a relative phase difference between the two output beams can be changed. Accordingly, characteristics of the composite coupler consisting of a plurality of stages of optical couplers can be designed as desired easily. |
